package org.ko.utils;

import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;

import javax.imageio.ImageIO;

public class ImageUtils {

	/**
	 * @param imgsrc 原图片的路径
	 * @param imgdist 新图片路径
	 * @param widthdist 新图片的宽度
	 * @param heightdist 新图片的高度
	 * @param rate 压缩的比例-不为null则等比例压缩
	*/
	public static void reduceImg(String imgsrc, String imgdist, int widthdist, int heightdist, Float rate) {
	        try {
	            File srcfile = new File(imgsrc);
	            // 检查文件是否存在
	            if (!srcfile.exists()) {
	                return;
	            }
	            // 如果rate不为空说明是按比例压缩
	            if (rate != null && rate > 0) {
	                // 获取文件高度和宽度
	                int[] results = getImgWidth(srcfile);
	                if (results == null || results[0] == 0 || results[1] == 0) {
	                    return;
	                } else {
	                    widthdist = (int) (results[0] * rate);
	                    heightdist = (int) (results[1] * rate);
	                }
	            }
	            // 开始读取文件并进行压缩
	            Image src = javax.imageio.ImageIO.read(srcfile);
	            BufferedImage tag = new BufferedImage((int) widthdist, (int) heightdist, BufferedImage.TYPE_INT_RGB);
	            tag.getGraphics().drawImage(src.getScaledInstance(widthdist, heightdist, Image.SCALE_SMOOTH), 0, 0, null);

	            //输出
	            String formatName = imgdist.substring(imgdist.lastIndexOf(".") + 1);
	            ImageIO.write(tag, formatName, new File(imgdist));

	        } catch (IOException ex) {
	            ex.printStackTrace();
	        }
	    }
	
	protected static int[] getImgWidth(File file) {
	    InputStream is = null;
	    BufferedImage src = null;
	    int result[] = { 0, 0 };
	    try {
	        is = new FileInputStream(file);
	        src = javax.imageio.ImageIO.read(is);
	        result[0] = src.getWidth(null); // 得到源图宽
	        result[1] = src.getHeight(null); // 得到源图高
	        is.close();
	    } catch (Exception e) {
	        e.printStackTrace();
	    }
	    return result;
	}


}
